[Geysers] Fan and Mortar history

Tara Cross fanandmortar at hotmail.com
Sun Dec 18 15:30:29 PST 2011

I have fairly complete records of Fan & Mortar from 2000 through 2011.

 are the numbers for the 2000-2005 active phase (ok, so this is probably
 more detail than anyone really wanted, but since I had the numbers in 
front of me, I thought I'd share):

First eruption:  January 2000 (missing exact date), followed by several intervals of a month or more.
July 8-late October:  intervals mostly 1-2 weeks
October 2000 to June 7, 2001:  intervals 3 1/2-14 days
June 7, 2001 to April 8, 2003:  intervals mostly 3-7 days; longest eruption of the "spring slowdown" in 2002 was only 9d21h38m
April 26-June 8:  mini-dormancy of 42d19h25m (longest interval of active phase)
June 8-December 20:  erratic intervals of mostly 4-11 days
Dec 20, 2003-January 24, 2004:  mini-dormancy of 35d01h14m
February 2004:  back to shorter intervals
March-June:  long, erratic intervals of 9-27 days
July-August:  short, regular intervals of 2 1/2-6 days EXCEPT for the shortest interval of the active phase, 1d15h56m
September-October:  erratic intervals 2-9 days
November 2004-March 2005  :  regular intervals 2 1/4-6 1/2 days
April-May:  spring slowdown, longest interval 16d01h21m
June-August 8:  regular intervals of 2-6 days
August 8:  active phase comes to a screeching halt with no warning

And, here are the numbers for the 2007-2011 active phase:

June 5, 2007:  first eruption, interval approximately 22 months
 2007-April 2008:  First interval 36 days, then intervals erratic, a few
 periods of 3-5 day intervals but some much longer ones thrown in (up to
April 2008-June 2008:  Mini-dormancy of at least 57 days (longest interval of active phase)
July 2008-November 2008:  intervals mostly 2 1/2-5 1/2 days with a little slowdown in October
November 2008-April 2009:  not much known, hard to know from occasional washed marker reports
April 25-May 31:  mini-dormancy of at least 35 days
June 2009-December 2010:  intervals mostly 3-6 days (longest interval of 2010 spring slowdown:  12d3h34m)
January-April 2011:  intervals 5-8 days
May 3-June ~18:  mini-dormancy of ~45-46 days
July-October 15:  intervals 2 1/2-6 days
 14-15 overnight:  last eruption of active phase; hard to tell if there 
was any warning due to most eruptions occurring at night

that's more than you ever wanted to know about F&M.  The 2007-2011 
active phase was a little more erratic than 2000-2005 with several 
mini-dormancies.  But both active phases had extended periods of very 
regular intervals, and *most* eruptions were preceded by "event 
cycles."  The nature of these evolved over time but thanks to radios, 
Fan & Mortar were certainly more seeable in the 2000s than ever 

--Tara Cross
fanandmortar at hotmail.com

> Date: Sat, 17 Dec 2011 23:18:39 -0500
> From: goldbeml at ucmail.uc.edu
> To: geysers at lists.wallawalla.edu
> Subject: [Geysers] Fan and Mortar history
> Between the season-ending reports that Fan and Mortar looked "broken" and 
> the lack of washed markers to start the winter, I have a sinking feeling 
> that they've gone dormant for the time being.
> I've cobbled together an incomplete history of F&M active phases over the 
> past 25 years.  Some of it is personal recollection.  Where possible I 
> have corroborated (or corrected) it using the OFVC logbook data posted 
> on GOSA's website.
> Dormant 1985-86?
> Active 1987-88
> Dormant or very infrequent 1989  (early issues of the Sput would know)
> Active 1990-94
> Dormant 1995-June 1996
> Active June 1996-May 1998
> Dormant May 1998-July 2000
> Active July 2000-August 2005
> Dormant August 2005-June 2007
> Active June 2007-October 2011
> In many of the active years, there is a seasonal period of longer 
> intervals (sometimes over a month) during the spring high water.
> The onset of actual dormancy appears to come at any time, often without 
> warning (2005 is a good example).
> On the flip side, once eruptions resume the intervals might drop right 
> away to their normal range.  Let's hope that happens again soon.
> Michael Goldberg
> michael.goldberg at uc.edu
> _______________________________________________
> Geysers mailing list
> Geysers at lists.wallawalla.edu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: </geyser-list/attachments/20111218/bd7f2410/attachment.html>

More information about the Geysers mailing list